As a message to your friend: 60% of bipolar people develop substance dependency in their lifetime. I wish I had known that before I started experimenting with drugs. I have been addicted to several, ODed many times, and was an intravenous user.
I'm actually still recovering from a nasty dependency to it (I am no longer dependent on any other drug) I've had for about two years now. I started using occasionally around the age of 15, having had "just" unipolar depression for 4 years at that point. I was fine with DXM then, had wonderful afterglows and a sense of gained knowledge from that drastically altered perception. It was still just temporary though, my depression was severe enough to warrant a hospitalization after a botched suicide attempt by hanging.
Bipolar I (severe) was diagnosed when I was 18, SSRIs being the direct cause of my first manic episode and therefore the diagnosis. DXM use started getting more frequent, but I could still stay off it for a while with only a twinge of cravings if I wanted to. By the time I reached the end of age 18, the ball really started to get rolling for chronic dependency with me struggling to keep up the limit of twice a month. In my 19th year of life I was institutionalized a further 5 times in that one year - all due to manic/psychotic episodes. However these were not acute drug-induced except for the last one from DXM, which was my first drug-induced psychosis. Nothing else has induced ever psychosis in me. This period of time I started doing it every week was whenever I wasn't in the institution and began noticing even more manic episodes occurring after the trip had ended. After I got out of involuntary commitment to rehab for "polysubstance dependency."
By then it developed seriously enough for me to start stealing so I wouldn't go completely broke and that all my attention was basically focused on the DXM and not really much else (though I would take them if I had the opportunity anyway). Once that phase started, I got manic EVERY single time and was having persistent psychotic tendencies (not schizoaffective). Somehow I managed to avoid any further institutionalizations because I was not violent.
I stopped 2 months ago. As an example of how potent DXM was at inducing mania, I've discovered methamphetamine and occasionally use it. I never acted manic during the high, which is normal in and of itself. This indicates to me that long-term chronic use of any drug is what fucks bipolar people over and that DXM is the only serotogenic drug I have tried outside many psychedelics, none of which ever induced an episode, presumably due to its very specific mode of action. Now that I am clean (well, I still chip every once in a while) I am doing better and noticing depression coming back for the first time since my dependency started, which is actually a good sign. I undeniably have bipolar disorder though as I already had it for quite a while before fucking around with drugs (diagnosis took about two years of observing its development), and that I almost got hospitalized/jailed yet again the other day for manic symptoms (which are still present and obvious with the length of this post) despite having done no drugs for the longest time since I can remember.
I don't really think DXM caused my disorder, but it aggravated it to a great degree and made it progress waaay faster as it is a disease that gets worse with age.
